cron window look-ahead + crontab docs (v1.0)

README.md

@@ -21,21 +21,36 @@ leaves native recurrence untouched (the two are mutually exclusive per card).
 - **Lead time:** "create the copy N days before the due date", so the card shows up early enough
   to act on; the copy is still due on the real day.
 
+## Scheduling (cron)
+
+The engine runs from the CLI command `recoreco:run`. Add it to cron **four times a day** -- at
+05:58, 11:58, 17:58 and 23:58:
+
+```
+58 5,11,17,23 * * * cd /path/to/kanboard && php cli recoreco:run >> /var/log/recoreco.log 2>&1
+```
+
+(Point the path at your install and run it as the user that owns Kanboard's data.) Each run looks
+ahead 12 hours; the runs overlap by 6 hours, so a single missed run is covered by the next one, and
+any occurrence whose time is already past is still caught up. `days before` shifts a copy earlier
+within that lead. You can also run it by hand any time: `php cli recoreco:run`.
+
 ## Status
 
-Early development. This version adds the **Recurring schedule** modal (a task sidebar action) and
-stores the settings in task metadata. The scheduling engine and the cron command arrive in the
-following versions.
+Working for **monthly by day** (with the last-day rule), driven by cron. The remaining frequencies
+(yearly, weekly, daily, monthly by weekday), the recurrence icons, and the FinanceBuddy
+installment hand-off arrive in the following versions.
 
 ## Requirements
 
 - Kanboard >= 1.2.0
+- cron (to run `recoreco:run`)
 
 ## Installation
 
 Copy this folder into your Kanboard installation as `plugins/RecoReco/`. The directory name must be
 exactly `RecoReco` (Kanboard derives the plugin namespace from the folder name). No build step and
-no database migration.
+no database migration. Then add the cron entry above.
 
 ## License